Rotary piston pump



Nov. 14, 1933. K, STELZER v y 1,934,890

ROTARY PpsToN PUMP Filed Aug. 6, 1931 ull;

llllllllll lllllllllllll Patented' Nov; 14,1933'v l UNITED 'STATES PATENT OFFICE ROTARY rrs'roN PUMP- Karl Steller, vienna, Austria, assignor to Oskar Smreker, Luzern, Switzerland Application August 6, 1931,v Serial No. 555,591,

and in Austria August 19, 1930 4 Claims. (Cl. 10S-126)I Heretofore rotary piston pumps provided with prevented by the arrangement of grooves or chanpistons which are arranged axially side by side, nels on the smooth outside ofthe pistons, wherejointly take up the whole circumference and are by the material drawn in between the piston and displaced at a certain angle to one another, are casing or piston and shaft is not pressed at but 5 constructedinsuchamanner that the radial faces ls pressed only along the vertex of the grooves 60 1 of thepistons are formed in accordance with the or channels. Thelatter are either ring-shaped rolling curves (tooth-profile curves) for th'e puror screw-shaped, whereby the parts of the iiuid pose of generating a tight closure throughout the present between pistons and casing or piston flanks, so that each pair of pistons constitutes an and shaft are fed forward by rotation in accordindividual pump independently from the axially ance with the screw-threads, which extend in 65v adjacent pair of pistons. accordance with the direction of feed.

The pump according to the present invention Some modes of carrying out the present in` does not consist of individual pumps but ofv a vention are illustrated by way of example on the battery of piston-parts which do not call fora accompanying sheet of drawings in which:-

tight closure at the flanks because the piston- Fig. 1 shows in sectional elevation the co- 7u parts, arranged side by side in the form of a.4 operating pairs of piston-parts. step screw, form in any position of rotation a Figs. 2, 3, 4 and 5 illustrate piston-parts with chamber (compartment) which is closed at both different Hanks. ends by the overlapping lateral faces of the pis- Figs. 6 and 7 are side views of the piston-parts ton-parts and axially moves during the .rota- Ashown in Figs. 4 and 5. -75 tion of Ythe piston-parts. The length of the Figs. 8 and 9 show a pump provided with lpermanently closed helical compartment corregrooved pistons in sectional plan View and in sponds to one complete rotation of the step screw. `vertical section respectively.

In view of this fundamental idea, according The pump comprises two cylindric rotary'memto which the packing or tightening rolling curves bers 1, 1 (Figs- 1 and 8) which are 00119166. With 80 are dispensed with which otherwise are necesone another by toothed wheels 10, l1 and on sary in-thelcase of individual pumps, it is possiwhich are arranged axially side by sidethe pisble according to the present invention to provide ton-parts 2, 2. The pistons thus formed are a clearance between two co-ordinated smooth enclosed in a casing 3, provided with an admisflanks inparallel position, said clearance allowsion part 11 and a discharge port 12 for the 85 ing the peripheral edges to move past the suruid. Each piston-part 2, 2 is displaced at a faces of the flanks without contact. certain angle with respect to the axially adjacent This idea of the present invention can be piston-part,'so that two-step screws are formed realized by dierent positionsof theank-faces. which leave a helical chamber 4 between their However a particular featureof the present inthreads. These chambers or compartments are 90 vention consists in inclining the flank-faces with closed at the periphery by the Wall 0f the 'CaS- lrespect to the axis of rotation for the purpose of ing and in the axial direction, after a complete promoting the axial feed ofthe uid, revolution of the step screw, by the overlapping Although a clearance remains between the lateral faces of the" corresponding piston-ports 40 flanks, so that a jamming by the flbresor any 2, 2' as indicated in Fig. 2 by the sectioned part 7. 95

other coarse constituents ofthe uid cannot take Therefore the length each chamber or complace, it is nevertheless necessary that the pistons partment in the axial direction from closure to of the rotary piston pumps pass close to the wall closure corresponds to 'the pitch of the screw of the casing or to the shaft of the opposite pisduring a complete revolution. During the rota- -ton. A. further object is to prevent the jamming tion of the members 1, 1 the chambers move 100 of bres or like constituents of the uid at these in the axial direction and thus feed the fluid. places. In the event of smooth surfaces the Therefore it is not necessary to make provision liquid is pressed out of the viscous and brinous for a tight closure at the radial flanks 5, 5'. In uid at the said places, while the solid' parts view thereof the latter are flat and according to of the uid are pressed flat against these places. this invention'leave between them a sumcient 105 These firmly adhering parts ofthe uid form clearance, that their peripheral edges 6, 6' can a kind of lining which hampers the rotation and move past the faces of the other accorded flanks. even may stop the pistons. Besides the feature of simpler manufacture of According to the present invention the presssmooth flanks of this kind, a further feature of liti ing flat of the solid constituents of the fluidis the present invention consists in that during the rolling action closed corner-spaces are not formed from which the fiuid can be displaced with difiiculty only, because the corner-space remains open owing to the provision of theclearance. This f is of the greatest importance when feeding viscous and flbrinous iiuids. The provision of the clearance has the further advantage that the operation is absolutely smooth and without shocks and that fibres do not adhere in case the clearance is enlarged beyond the size necessary for the movement. It is of advantage to round off or chamfer the peripheral edges in order to prevent the cutting or tearing of the fibres. The edges 8, 8' and 9, 9 (Fig. 1) facing the axis of rotation can be rounded off or chamfered for the purpose of facilitating the axial feed of the fluid within the working compartments.

' In the construction shown in Fig. 2, the flanks 5, 5 are disposed parallel to a plane, passing through the piston-axes, in the moment in which the anks are positioned parallel to one another. In view of the arrangement of the clearance, the sum of the peripheral angle of two coordinated piston-parts is less than 360 degrees. In the event of like piston-parts, the clearance is disposed symmetrical with respect to a plane passing through the piston-axes. The position of the clearance becomes unsymmetrical with `respect to this plane if the two co-ordinated piston-parts are of; unlike length, without altering the kefciency of the pump.

In the construction shown in Fig. 3, theflanks 5, 5 are inclined with respect to a plane, passing through the piston-axes, in the moment in which the flanks are positioned parallel to one another.

As shown in Figs. 1, 4, 5, 6 and 7, the flanks 5, 5 may be suitablyA inclined with respect to the axis of rotation, in order to promote the axial feed of the uid, present between the flanks.

The passing in the direction of the axis of rotation may be rounded off or chamfered in order to promote the flow and the displacement of the fluid in accordance Awith the progressing screw-thread.

If desired only the advancing or forward edges may be rounded off or chamfered in accordance with the direction of rotation of the piston However also all edges may be rounded off or chamfered if required.

The outside of the rotary pistons of the pump shown in Figs. 8 and 9 is provided with grooves 13, in order to prevent the jamming of bres or like. The grooves may be ring-shaped or screwshaped as illustrated. The screw-shaped grooves feed the jammed material in an axial direction in the compartment 4.

Pistons provided with grooves may be also used in connection with rotary piston pumps of other constructions.

1. A` rotary piston -pump particularly adapted for pumping viscous and flbrinous fluids cornprising in combination a casing and parallel pistons arranged therein and consisting of a battery of interengaging rotary piston-parts disposed side by side in the form of a step screw, the anks of said piston-parts being in the shape of flat faces inclined at the same angle with respect to their axis of rotation. 2. A rotary piston pump particularly adapted for pumping viscous and brinous fluids comprising in combination a casing and parallel pistons arranged therein and4 consisting of a battery of interengaging Vrotary piston-parts disposed side by side in the form of a step screw, the flanks of said piston-parts being in the shape of flat faces inclined at the same angle with respect to their axis of rotation and further inclined in the parallel position with respect to the plane passing through both axes of rotation of the piston.

3. A rotary piston pump particularly adapted for pumping viscous and fibrinous uids com-- prising in combination a casing and parallel pistons arranged therein and consisting of a battery of interengaging rotary piston-parts dis'- posed'side by side in the form of a step screw,

the anks of said piston-parts being in the shape flanks of the piston-parts forming in any position of rotation a clearance allowing the peripheral edge of one flank to move past the other flank without contact.

4. A rotary piston pump particularly adapted for pumping viscous and fibrinous fluids comprising in vcombination a casing and Aparallel pistons arranged therein and consisting of a battery of interengaging rotary piston-parts disposed side by side in the form of a step screw, the flanks of said piston-parts being in the shape of flat faces inclined at the same angle with respect to their axis of rotation and further inclined in the parallel position with respect to the plane passing through both axes of rotation of the piston, and two co-ordinated flanks of the piston-parts forming in any position of rotation 

